In a television receiver, a tuner is used to convert a radio frequency (RF) signal to an intermediate frequency (IF) or baseband signal, and a demodulator is used to remove the signal modulation added for transmission. Traditionally, the tuner and demodulator are implemented in separate chips or modules. The IF or baseband signal is typically sent from the tuner to demodulator as a real analog signal, or complex analog signal. This requires analog-to-digital (A/D) conversion in the demodulator chip. The inclusion of the A/D function in a largely digital demodulator chip adds complexity and cost.
Recently, tuners have been developed that perform some of their signal processing in the digital domain. Hence they have an A/D conversion function. Such tuners therefore also provide a digital-to-analog (D/A) conversion capability to allow them to interface with traditional demodulators. This adds redundancy in the form of D/As in the tuner and A/Ds in the demodulator that waste power, area, and add complexity to the development of these chips.